1. Field of the Invention
This invention relates to a method and an apparatus for recording and/or reproducing to and from a recordable disk previously provided with absolute addresses, wherein a program area and a lead-in area are provided on the disk, the data such as the performance information is recorded in the program area, an archival information, that is, the table of contents or TOC information, showing the record contents in the program area, the recorded in the lead-in area, and wherein the program area is reproduced on the basis of the TOC information recorded in the lead-in area. The present invention may be applied for example to apparatus for a recordable and reproducing compact disk.
2. Description of the Prior Art
The disk player dedicated to reproduction, such as the CD player, adapted to reproduce a so-called compact disk (CD) in which audio signals such as speech or musical sounds are digitized and recorded on an optical disk, has been presented and made available to the market. In the compact disk, the TOC information showing the record contents of the disk, such as the time code sequentially indicating the start time points of the tunes recorded in the program area, the tune numbers of the first and last tunes, the time points at which the performance of the last tune is terminated, etc. is recorded in the lead-in area provided inside the program area. The CD player is so designed as to reproduce the TOC information recorded in the lead-in area of the disk first of all and to reproduce the performance information of the tunes from the program area on the basis of the TOC information or to perform the programmed reproduction.
In consideration of the fact that the conventional CD player is dedicated to reproduction, attempts have been made to develop a disk system which, through the use of an opto-magnetic disk formed of a post-writable opto-magnetic recording medium, may be adapted for recording and reproduction to maintain upper compatibility with respect to the compact disk.
The recordable disk 1 employed in the disk system is formed with a number of spirally extending pre-grooves 2 each having a depth of .lambda./8, .lambda. being the wavelength of the laser light used for recording the information, as shown in the diagrammatic view of FIG. 1. On each land 3 between the adjacent pre-grooves 2, pre-recorded areas 4 where a series of patterns of projections and recesses formed by pits .lambda./4 deep are previously recorded in the circumferential direction are formed alternately with data record areas 5 where opto-magnetic recording is performed. On the inner side of the program area 6 of the recordable disk 1 where the performance information is recorded, there is formed a lead-in area 7 where the TOC information showing the record contents of the program area 6 is recorded. In the pre-recorded area 4 of the recordable disk 1, there are recorded 24-bit synch signals and 14-bit or 1-symbol sub-code signals as patterns of projections and recesses obtained by molding, these sub-code signals being absolute time information or absolute addresses commencing from the start position of the program area 6. These sync and sub-code signals are among 588 channel- bit eight to fourteen modulation or EFM data including in addition to the aforementioned sync and sub-code signals, 14.times.32 bit or 32-symbol data such as the performance information, parity data and 3 margin bits between the adjacent symbols, these constituting each form of the data format standardized in the compact disk, as shown in FIG. 2.
In the disk system employing the recordable disk 1, the rotational velocity of the disk is controlled to a constant linear velocity (CLV) by taking advantage of the absolute address reproduced from the pre-recorded area 4 of the recordable disk 1, so that the performance information, for example, is recorded in accordance with the data format standardized in the compact disk (CD), while the TOC information indicating the sequence of the recorded information units, for example, is recorded in the lead-in area 7. The information units in the program area 6 are sequentially reproduced in accordance with the TOC information contained in the lead-in area 7.
It will be noted that, in a disk system providing for both recording and reproduction and designed to be in the relation of upper compatibility with respect to the compact disk, it may occur that the tunes recorded in the program area of the recordable disk are not in the correct sequence. For example, when a new tune is recorded in a non-recorded area between two adjacent tunes, or when a new tune is re-recorded in the previously recorded area, the sequence of the previously recorded tunes necessarily becomes indefinite.
On the other hand, certain disk recording and/or reproducing apparatuses are so designed that the TOC information indicating for example the sequences of the tunes or record information units is automatically formed and recorded in the lead-in area of the recordable disk, on the assumption that a silent period continuing for longer than a predetermined time represents the period between the adjacent tunes, the information units in the program area being sequentially reproduced on the basis of the so-formed TOC information. In classical music where continuing silent periods are frequently encountered, although these periods do not represent the periods between the tunes, the TOC information is recorded in the lead-in area as if plural tunes were recorded in the program area when only one tune is actually recorded therein, so that a complicated operation becomes necessary to perform management of the respective information units recorded in the program area.